Pop legend Whitney Houston was apparently found unresponsive in her bathtub at the Beverly Hilton Hotel, with bottles of prescription sedatives in her room. The cause of the singer’s death at age 48 has not been confirmed as an overdose — and the results of a toxicology report may not be available for weeks — but the circumstances bear many of the hallmarks of such a death.

Like most overdose victims, Houston had a long history of addiction. Her ongoing and distressingly intense battle with cocaine had received extensive media coverage. She had tried rehab at least three times; her latest stay was last May. Like her, the majority of overdose victims typically attempted rehab previously.

Victims of unintentional overdose also show clear signs of drug misuse before or at the time of their death. In a 2008 study in West Virginia — a state with a high rate of overdoses — researchers found signs of drug misuse, including shooting drugs intended to be taken orally or drinking alcohol while taking depressant drugs like Xanax, in 95% of the deaths.

In the days before Houston’s death, she was seen drinking excessively — something that is not recommended for people who are in recovery from other addictions, especially if they’ve only recently left rehab. Some people find that their addictions are limited to particular substances, but for many others, alcohol increases the likelihood that they’ll return to their drug of choice. Alcohol — even just one drink — tends to lower inhibitions, which can thwart people’s ability to avoid taking other drugs.

Houston’s age also fits the profile of typical overdose victims. Although we think of drug abusers as invariably young, there are actually three periods during addiction, at different ages, when death risks are highest.

The first is when the user is inexperienced — which does tend to apply to young people — but these deaths are much less common than in older users. The second risk period is just after of a bout of abstinence, whether the person is forcibly made (as in prison) or volunteers to stop using. Becoming abstinent reduces the tolerance to drugs that people build up during addiction, which leaves them at greater risk of overdose from the same amount of drugs that they formerly took safely.

The third period of high risk is middle age. Indeed, according to the CDC [PDF], the largest proportion of overdoses occurs among people ages 45-54, with the second largest group at ages 35-44. Men are more likely to die than women, however: two-thirds of overdose deaths occur in men, reflecting the higher prevalence of addiction in males.

Houston’s death stands out in that — so far, at least — it does not seem to have been associated with prescription opioid painkillers, which are found in 40% of overdose victims. Most overdoses involve some combination of sedative drugs other than opioids, including alcohol and benzodiazepines like Valium (diazepam) and Xanax (alprazolam). Prescription drugs said to have been found in bottles in Houston’s hotel room include Xanax, Valium and Ativan (lorazepam); all three are benzodiazepine antianxiety medications.

Taken in combination with one another — especially with alcohol on top — these drugs can be fatal. They can leave people vulnerable to drowning in shallow water (as in the bathtub where Houston was found) or choking to death on vomit.

There are some important ways to reduce the risk of overdose. Obviously, the first is not to take drugs to begin with, but for those who don’t heed that advice, it’s important to not mix drugs that have the same kind of effects, particularly not those that have a depressant or sedative effect, known as “downers.” Mixing stimulants like cocaine and amphetamine is also a bad idea, but it is less likely to result in death than combining drugs that slow or, at high doses, stop respiration.

For overdoses involving opioids, the problem can be reversed with an antidote known as Narcan (naloxone) if caught quickly enough. The drug, which is safe and nonaddictive, is distributed at needle-exchange programs and other locations in some states (call 311 in New York City to find sites in the five boroughs), but most people still don’t know about it or have access to it.

Few overdose victims have the talent of Whitney Houston. But while we mourn the loss of a legend who had great difficulty achieving recovery, we should consider how to prevent similar deaths. It is important to educate people who are at particular risk of overdose — such as those leaving treatment or prison — about the tolerance effect, the danger of mixing sedatives and the existence of naloxone if relevant. Making naloxone available over the counter also could make a real difference in reducing death rates.

Addiction is often chronic and marked by relapse. But overdose ends all hope of recovery.